tmp_摄像头控制接口
V4L2应用程序开发
参考资料：
- mjpg-streamer：https://github.com/jacksonliam/mjpg-streamer
- video2lcd：这是百问网编写的APP，它可以在LCD上直接显示摄像头的图像
- 这2个源码都放在GIT仓库里：
1.
To be able to manipulate the physical properties of a video function, its functionality must be divided into addressable entities. The following two generic entities are identified:
- Units：Selector Unit 、Processing Unit 、Encoding Unit 、Extension Unit
- Terminals ：Input Terminal (IT) 、Output Terminal (OT) 、Camera Terminal (CT)
- A Camera Terminal is always represented as an Input Terminal with a single output pin. It provides support for the following features
- Scanning Mode (Progressive or Interlaced)
- Auto-Exposure Mode
- Auto-Exposure Priority
- Exposure Time
- Focus
- Auto-Focus
- Simple Focus
- Iris
- Zoom
- Pan
- Roll
- Tilt
- Digital Windowing
- Region of Interest
Controls have attributes, which might include:
- Current setting
- Minimum setting
- Maximum setting
- Resolution
- Size
- Default
Processing Unit
- User Controls
- Brightness
- Hue
- Saturation
- Sharpness
- Gamma
- Digital Multiplier (Zoom)
- Auto Controls
- White Balance Temperature
- White Balance Component
- Backlight Compensation
- Contrast
- Other
- Gain
- Power Line Frequency
- Analog Video Standard
- Analog Video Lock Status
Extension Unit
对于每一个entity(IT,PU,SU,OT等)
- IT: input terminal
- OT：output terminal
- VC: video control
video function：含有几个interface，每个video function含有一个VC(video control)、多个VS(video streaming)，它们被称为VIC。
参考资料：